Touch display panels have been widely used in various kinds display devices, such as liquid crystal display (LCD). When an image is displayed by the display device, a user may contact (e.g., by pressing or touching) the touch display panel to generate touch events and control the device.
One kind of the touch display panel is called self in-cell touch display panel, in which a plurality of touch sensing lines are used as touch sensing electrodes in a touch mode of the display device and used as common voltage (Vcom) electrodes in a display mode of the display device.
However, this kind of touch display panels need extra metal layer for forming the touch sensing lines, resulting in a high cost of the manufacturing process. In order to solve this issue, the industry has tried to dispose the touch sensing lines parallel with the data lines in the same metal layer, but this would significantly reduce the aperture ratio of the display device.